Thanks to all, some interesting figures to digest. Will do some more research now that I have something to base it on. Thanks again.
> -----Original Message----- > From: DaZZa [mailto:[EMAIL PROTECTED]] > Sent: Tuesday, 16 July 2002 4:12 PM > To: Simon Bryan > Cc: Slug > Subject: Re: [SLUG] Backup systems > > > On Tue, 16 Jul 2002, Simon Bryan wrote: > > > At the moment the only ones being succesfully backed up are the Windows > > boxes using the built in software, these are gpoing to tape > (DDS), but this > > is obvioulsy nowhere near enough. The total of data on the > Windows systems > > may get up to only around 10 -20 GB. > > > > My hope is to have a backup server that is doing all the work > for all the > > systems. I can do this under Windows with some expensive software and > > hardware utilising SAMBA to get the Linux based data (could > work the other > > way as well). We are a school, so have a relatively large window of > > opportunity for backups to take place overnight. We do have > internet access > > to the AUC system but most of this dies around mid-night and > that is all web > > based access. > > You're shit out of luck. > > Large scale backups - regardless of platform - are hideously expensive. A > tape library {given that the largest tape drive I know of is only about a > max of 80 gig per tape} will set you back literally tens of thousands of > dollars - alternately, you get someone to change the tape when it's full, > but have to pay them wages to sit around all night waiting. > > > Does there exist a sutiable robust Linux system? I would > imagine that most > > of the bcakups would go to another HDD on another machine, and > then to tape > > from there. > > There's plenty of software to do the job. Hell, tar will do it just fine. > The problem is your hardware, as mentioned above. With that much data to > backup every night, you're going to span tapes - and you need some way to > enable this. > > > We have a 128K ISDN line which could also be utilised if needed, > > but that would be last resort stuff. > > 80 gig over a 128k ISDN line? Every night? Are you serious? > > Look at the numbers. > > 80 gig is 8.589934592 times 10 to the 10th power bytes. > > {Someone can check my math if they like. I figured it like this > > 1024 bytes times 1024 equals one megabyte, or 1048576 bytes. Multiply this > by 1024 again to get a gigabyte - or 1073741824 bytes. Multiply this by 80 > to get 80 gigabytes.} > > A 128k line {that's 128 kiloBITS per second} will move, at most, allowing > nothing at all for protocol overhead {which would have to be included, but > I'm only looking at pure figures here} 16000 bytes per second. That's > 960000 bytes per minute. Or 57600000 bytes per hour. > > At that rate, moving your data would take 1491.31 hours. > > Or 62 and a bit days. > > > I am still relatively uninformed as to these larger backup > systems processes > > and problesm so would appreciate advice from anyone doing something in a > > similar sized and configured system > > If you want a daily FULL backup of everything, you're going to need a tape > changer {or a bigger tape drive than I am aware of, which may be > possible}. > > What you need to consider is a backup regeim which only performs > incrimental backups for most of the week, with a full backup happening > once a week - then you will fit most of your backup on one tape daily, and > only have to worry about changing tapes once a week. > > Works something like this. > > Sunday - full backup > Monday - Files changed Monday backed up. > Tuesday - Files changed Monday & Tuesday backed up. > Wednesday - Files changed Monday, Tuesday and Wednesday backed up. > Thursday - Files changed Monday, Tuesday, Wednesday and Thursday backed > up > Friday - Files changed Monday, Tuesday, Wednesday, Thursday and Friday > backed up. > > You can include Saturday if you want {if necessary}, or move your full > backup to Friday night to avoid one set of incrimental backups. > > TAR contains the ability to to differential backups {as far as I know}, > and a suitable script could be written to do this. Alternatively, you > could run something like Veritas or ArcServe on one of the WindoZe boxes, > and backup the Linux stuff via samba. > > The option of backing up to another hard disk is viable, but you're going > to need a lot of disks to keep the required amount of data. Legally, if > you're backing up financial transactions, you're required to keep 15 YEARS > of backups - and if you don't, and can't provide the data if the tax > office asks for it, you're in deep do-do. > > Either way, you're gonna have to spend a fair bit of money. > > DaZZa -- SLUG - Sydney Linux User's Group - http://slug.org.au/ More Info: http://lists.slug.org.au/listinfo/slug
